Reactive stimulation of oil and gas wells

Abstract

A method and apparatus for stimulating producing strata in oil or gas wells. The formation is penetrated using shaped charges, and an oxygen-rich material then is introduced into the producing formation. Thus, oxygen is available within the formation to sustain an explosive reaction with the existing formation hydrocarbons acting as fuel. This explosive reaction will cause fracturing of the formation and will counteract plugging that often results from the use of conventional shaped charges. In one embodiment, a container encloses shaped charges surrounded by oxygen-rich material. Alternately, the oxygen can be a part of the shaped charge and projected into the formation with the shaped charge to accomplish the same results. Still further, oxygen-rich material can be pumped into the well in bulk in a liquid or paste form.

1. An apparatus for stimulating production from a hydrocarbon-containing formation in an oil or gas well, the apparatus comprising:
 a container sized to be received and supported in the well at a level adjacent the formation; 
 at least one shaped charge supported within the container, the shaped charge comprising:
 a housing with a rear portion and a front portion; 
 a body of fast burning explosive in the rear portion of the housing, the front of the body defining a rearwardly pointing conical recess; 
 a rearwardly pointing conically-shaped liner fittingly positioned in the conical recess of the front of the body of fast burning explosive; 
 a detonator adapted to ignite the body of fast burning explosive; and 
 a body of oxygen-rich material in the frontal portion of the housing in front of the body of fast burning explosive and the liner wherein the oxygen-rich material is not explosively reactive with water and that is capable of fueling the burning of hydrocarbons in the formation; 
 whereby the shaped charge is adapted to perforate the formation and the body of oxygen-rich material is adapted to be introduced explosively into the formation with the shaped charge whereby burning of hydrocarbons therein is promoted regardless of the presence of water in the well when the explosive is ignited; 
 
 at least one igniter for detonating the shaped charge. 
 
   
   
     2. The apparatus of  claim 1  wherein the at least one shaped charge comprises a plurality of shaped charges positioned to perforate different locations in the formation. 
   
   
     3. The apparatus of  claim 1  wherein the oxygen-rich material is potassium nitrate. 
   
   
     4. The apparatus of  claim 3  wherein the at least one shaped charge comprises a plurality of shaped charges positioned to perforate different locations in the formation. 
   
   
     5. The apparatus of  claim 1  wherein the apparatus further comprises a high order primer cord in contact with each of the at least one shaped charge. 
   
   
     6. The apparatus of  claim 1  wherein the igniter is an electric igniter. 
   
   
     7. The apparatus of  claim 1  wherein the front of the housing is dome-shaped and wherein the oxygen-rich material is generally hemispherically shaped. 
   
   
     8. The apparatus of  claim 7  wherein the rear face of the body of oxygen-rich material is flat. 
   
   
     9. The apparatus of  claim 8  wherein the rear face of the oxygen-rich material is adjacent the edge of the liner. 
   
   
     10. The apparatus of  claim 8  wherein the rear face of the oxygen-rich material is spaced a distance from the edge of the liner. 
   
   
     11. The apparatus of  claim 7  wherein the body of oxygen-rich material has a central bore therethrough. 
   
   
     12. The apparatus of  claim 11  wherein the rear face of the body of the oxygen-rich material is flat. 
   
   
     13. The apparatus of  claim 11  wherein the rear face of the body of the oxygen-rich material is frusto-conically shaped. 
   
   
     14. The apparatus of  claim 7  wherein the rear face of the body of oxygen-rich material is frusto-conically shaped. 
   
   
     15. A shaped charge for use in perforating hydrocarbon-containing formations in oil and gas wells, the shaped charge comprising:
 a housing with a rear portion and a front portion; 
 a body of fast burning explosive in the rear portion of the housing, the front of the body defining a rearwardly pointing conical recess; 
 a rearwardly pointing conically-shaped liner fittingly positioned in the conical recess of the front of the body of fast burning explosive; 
 a detonator adapted to ignite the body of fast burning explosive; 
 a body of oxygen-rich material in the front portion of the housing in front of the body of fast burning explosive and the liner wherein the oxygen-rich material is not explosively reactive with water and is capable of fueling the burning of hydrocarbons in the formation; and 
 whereby the shaped charge is adapted to perforate the formation and the body of oxygen-rich material is adapted to be introduced explosively into the formation with the shaped charge whereby burning of hydrocarbons therein is promoted regardless of the presence of water in the well when the explosive is ignited. 
 
   
   
     16. The shaped charge of  claim 15  wherein the front of the housing is dome-shaped and wherein the oxygen-rich material is generally hemispherically shaped. 
   
   
     17. The shaped charge of  claim 16  wherein the rear face of the oxygen-rich material is flat. 
   
   
     18. The shaped charge of  claim 17  wherein the rear face of the oxygen-rich material is adjacent the edge of the liner. 
   
   
     19. The shaped charge of  claim 17  wherein the rear face of the oxygen-rich material is spaced a distance from the edge of the liner. 
   
   
     20. The shaped charge of  claim 16  wherein the body of oxygen-rich material has a central bore therethrough. 
   
   
     21. The shaped charge of  claim 20  wherein the rear face of the body of the oxygen-rich material is flat. 
   
   
     22. The shaped charge of  claim 20  wherein the rear face of the body of the oxygen-rich material is frusto-conically shaped. 
   
   
     23. The shaped charge of  claim 16  wherein the rear face of the body of oxygen-rich material is frusto-conically shaped. 
   
   
     24. The shaped charge of  claim 15  wherein the oxygen-rich material is potassium nitrate. 
   
   
     25. A method for stimulating a hydrocarbon-containing formation in an oil or gas well, the method comprising:
 non-explosively injecting a supply of oxygen-rich material into the formation; 
 after injecting the supply of oxygen-rich material into the formation, perforating the formation using a shaped charge. 
 
   
   
     26. The method of  claim 25  wherein the oxygen-rich material is potassium nitrate. 
   
   
     27. The method of  claim 25  wherein the shaped charge comprises:
 housing with a rear portion and a front portion; 
 a body of fast burning explosive in the rear portion of the housing, the front of the body defining a rearwardly pointing conical recess; 
 a rearwardly pointing conically-shaped liner fittingly positioned in the conical recess of the front of the body of fast burning explosive; 
 a detonator adapted to ignite the body of fast burning explosive; and 
 a body of oxygen-rich material in the front portion of the housing in front of the body of fast burning explosive. 
 
   
   
     28. The method of  claim 25  wherein the injection step is carried out using a tubing-conveyed injection device.